dma-mapping: add DMA_xxBIT_MASK to feature-removal-schedule.txt

DMA_xxBIT_MASK macros were marked as deprecated in June 2009.  One more
year is long enough, I think.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>